Optical fiber transmitters use a variety of different light sources, including Vertical Cavity Surface Emitting Lasers (VCSEL); Light Emitting Diodes (LED); lasers, and other light-emitting devices. However, due to variations in the manufacturing process, the individual produced transmitters have dissimilar behaviors. Furthermore, the output properties of these optical sources change with temperature as well. Therefore, each transmitter is first characterized to determine its output response, and then is subsequently adjusted to make its response comply with the required specifications. For example, bias current and modulation current of the transmitter may need to be adjusted so that its minimum and maximum power output levels fall within acceptable limits. This process of adjusting the transmitter to change its output response is referred to as “programming” the transmitter.
The prior art conventional programming method is to connect a pattern generator to the transmitter input, connect an optical power meter at the transmitter output, and then change the temperature while characterizing and programming the transmitter's output response to different inputs and at different temperatures to bring its performance in line with specifications.
Unfortunately, the pattern generators and optical power meters used for measuring the output characteristics are expensive, and the number of devices that can be simultaneously tested is constrained by the number of test pattern generators and power meters available. These constraints are especially limiting during the temperature characterization because it is such a time-consuming process.